I agree with your position that another toxicology newsgroup is not needed
at this time. It appears that the logic for the separation of medical
toxicology and environmental toxicology is an artificial one, without a
factual substantiation. As the moderator of the bionet.toxicology
newsgroup, you should be in a good position to verify the time when the
number and topical nature of the posts warrent a fragmentation of
toxicology on the net.
Frankly, I'm a generalist and have interest in medical, environmental,
pharmaceutical, and occupational toxicology as well as pharmacognosy and
the associated toxicities with plant and other living things. Therefore,
I would prefer a one-stop newsgroup.